1. Field of the Invention
The present invention relates to an apparatus for dehumidification of gas and comprising a regenerable vapor or moisture adsorbing medium or adsorbent. Such apparatuses for dehumudification of air or other gaseous mediums may, for example, be used for dehumidifcation of air in pressurized air systems and in rooms, and for dehumidification of gas or air which is used in manufacturing processes, etc.
2. Description of Prior Art
The prior art comprises apparatuses of that type in which the adsorbing medium or adsorbent is divided into a plurality of layers in order to obtain a more uniform distribution of gas flow over the cross-sectional area of the adsorbent used (such aparatuses are disclosed for example in U.S. Pat. Nos. 3,490,201 and 3,594,990). When the adsorbing medium or adsorbent has been used for a certain period of time and enriched with a certain amount of moisture it must be regenerated. This may be done by passing heated air through the adsorbent (U.S. Pat. No. 3,490,201) or by directly heating the adsorbent and simultaneously passing air from the ambient atmosphere therethrough (U.S. Pat. No. 3,594,990). The first mentioned regenerating procedure involves a relatively high loss of heat energy while the latter procedure is more advantageous from a heat economical point of view. However, in the known apparatus in which the adsorbing medium is divided into a plurality of layers, each of which is heated by electrical heating means during the regenerating step (U.S. Pat. No. 3,594,990), the layers of adsorbing medium are confined to small amounts of a desiccant, such as lithium chloride, deposited on heating wires by impregnation of asbestos yarn covering said wires. It is understood that the cost of the electrical heating device included in that known structure is relatively high compared to the adsorbing capacity of the adsorbent or desiccant supported by the heating device.
While some of the known apparatuses are operating intermittently, because the adsorbing and regenerating processes are alternating for the complete amount of adsorbent in the apparatus, other known apparatuses (disclosed for example in U.S. Pat. Nos. 3,487,608 and 3,490,201) may operate continously.